Internal combustion engine having at least one catalyst unit

ABSTRACT

An internal combustion engine having at least one catalytic converter unit for cleaning the exhaust gases produced during the operation of the internal combustion engine. The internal combustion engine includes at least one catalytic converter body which is arranged upstream of an exhaust gas heat exchanger in an exhaust gas flow path, especially an exhaust gas recirculation line.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a National Stage Application of PCT International Application No. PCT/EP2012/058978 (filed on May 15, 2012), under 35 U.S.C. §371, which claims priority to Austrian Patent Application No. A 835/2011 (filed on Jun. 6, 2011), which are each hereby incorporated by reference in their respective entireties.

TECHNICAL FIELD

Embodiments relate to an internal combustion engine having at least one catalytic converter unit for cleaning the exhaust gases produced during the operation of the internal combustion engine, comprising at least one catalytic converter body which is arranged upstream of an exhaust gas heat exchanger in an exhaust gas flow path, especially an exhaust gas recirculation line.

BACKGROUND

The engine industry is under high pressure to produce engines with especially low emissions. In order to reduce emissions to the environment, it is necessary for internal combustion engines, especially large engines and preferably large diesel engines, to provide treatment and cleaning of the exhaust gases outside of the engine for the purpose of maintaining statutory regulations. Cleaning of the exhaust gases outside of the engine usually occurs by means of a single catalytic converter unit. The exhaust gases emitted from the large engines are usually cleaned in an exhaust gas recirculation apparatus which is provided downstream of the large engine and subsequently partly supplied back to the large engine again. The exhaust gases are cleaned by a catalytic converter unit within the exhaust gas recirculation apparatus and subsequently supplied to an exhaust gas heat exchanger, especially an exhaust gas cooler. In the case of conventional exhaust gas coolers, the depositing of exhaust particulates occurs on the cooled inner walls of the exhaust gas cooler. In order to reduce hydrocarbons which react with the exhaust particulates and deposit on the cooled inner walls of the exhaust gas cooler in form of an adhesive layer, an oxidation converter usually arranged in a catalytic converter unit is provided upstream of the exhaust gas cooler.

An exhaust gas heat exchanger is known from WO 2005/028 848 A1, especially an exhaust gas cooler for exhaust gas recirculation in motor vehicles with a single diesel oxidizing converter, which is arranged in the intake port of the exhaust gas heat exchanger. The catalytic converter is provided upstream of the exhaust gas cooler. The substrate of this diesel oxidizing converter fills the entire cross-section of the intake port of the exhaust gas heat exchanger. As a result, a large amount of substrate is required for filling the entire cross-section of the intake port. Furthermore, no homogeneous flow profile is obtained by the shape of the diffuser of the intake port due to the configuration, so that the peripheral regions of the diffuser hardly encounter any incoming flow. Furthermore, the diesel oxidizing converter leads to a high flow resistance due to its configuration. Especially in view of the attachment of the diesel oxidizing converter in the intake port of exhaust gas heat exchanger, this concept is consequently disadvantageous to large piece numbers and therefore not suitable.

German Patent Publication No. DE 10 2005 014 385 A1 discloses an exhaust gas cooler for exhaust gas recirculation in motor vehicles, comprising heat transfer ducts through which exhaust gas flows and around which a coolant flows, which ducts open into a distribution and/or collecting chamber, and comprising a flow guide apparatus which is arranged in the distribution and/or collecting chamber and which comprises flow channels extending from the exhaust gas inlet area to the exhaust gas outlet area. The flow guide apparatus is formed by a catalytic converter.

An exhaust gas reaction apparatus for an internal combustion engine is known from German Patent Publication No. DE 26 35 725 A1, which comprises in the exhaust gas duct an arrangement of several ducts extending in the longitudinal direction and formed by mutually parallel walls which are in contact with each other, which ducts extend over the entire length of the reaction apparatus and whose walls are thin in relation to the duct width. The length of the exhaust gas reaction apparatus is between 30 mm and 100 mm, indicating that the specifications concern a small engine such as a vehicle engine.

Furthermore, German Patent Publication No. DE 195 23 532 A1 discloses a catalytic converter arrangement with exhaust gas guidance with two or more strands for motor vehicles, wherein the exhaust gas is guided in at least two separate systems in partial areas of the exhaust gas system. At least one catalytic converter with axially extending ducts is arranged in each system, wherein the catalytic converter is arranged in form of a single honeycomb body which comprises at least one separating wall on at least one face side which divides the cross-section of the housing and which is guided at least in a virtually sealing manner to the face side of the honeycomb body.

The aforementioned publications disclose conventional catalytic converter arrangements with a catalytic converter body which comprises a catalytic converter carrier which respectively forms axial flow ducts for the exhaust gas.

Conventional catalytic oxidation converters require a specific volume which depends on the engine size in order to efficiently implement oxidation. This volume of the oxidizing converter is usually achieved over a large length and over a small cross-section, because a larger cross-sectional area of the oxidizing converter is not possible due to production, installation conditions and other conditions relating to constructional dimensions. Usually, the length is achieved either by a long catalytic converter body with a small cross-section or by several catalytic converters which are arranged one behind the other in series along the longitudinal axis of the catalytic converter system and which are known from catalytic converter technology. This leads to a higher pressure loss between the inlet and the outlet of the catalytic converter unit. Furthermore, the several catalytic converters which are arranged one behind the other in series along the longitudinal axis are realized by solutions which are complex with respect to their construction and are expensive in their configuration.

SUMMARY

On the basis of this state of the art, the invention is based on the object of providing an internal combustion engine with at least one catalytic converter unit for cleaning the exhaust gases produced during the operation of the internal combustion engine, in which the pressure loss between the inlet and the outlet of the catalytic converter unit is reduced and therefore the influence on the engine output is lower. Furthermore, the catalytic converter unit shall be easy to install. In addition, optimized flow through the catalytic converter unit shall be provided.

This object is achieved in accordance with the invention in such a way that at least two or more catalytic converter bodies through which the exhaust gas can flow in parallel are arranged at maximum density over the cross-section.

The catalytic converter bodies are formed by substantially identical modules which are inserted adjacent to one another into the catalytic converter housing. Each catalytic converter body consists of a catalytic converter carrier with catalytic converter material arranged within a tubular catalytic converter sleeve.

The internal combustion engine in accordance with the invention offers considerable advantages over the state of the art concerning the configuration of the catalytic converter unit and its positioning. A lower pressure loss is achieved between the catalytic converter inlet and the catalytic converter outlet and a lower influence on the engine output is achieved for example by the configuration of the catalytic converter unit in accordance with the invention with two or more catalytic converter bodies through which the exhaust gas can flow in parallel and which are arranged at maximum density over the cross-section. These advantages arise from the reduction in the length of the catalytic converter unit and the expansion of its cross-section. The catalytic converter unit of the internal combustion engine in accordance with the invention is therefore provided with a highly advantageous compact construction. In addition, the configuration of the catalytic converter unit in accordance with the invention leads to a reduction in its weight.

One important advantage of the internal combustion engine in accordance with the invention with at least one catalytic converter unit is that the catalytic converter body, which previously needed to be attached with a large amount of work, can now be integrated in the catalytic converter unit in a simple way as a result of the configuration in accordance with the invention. A further advantage of the subject matter of the invention is the provision of a substantially homogeneous flow profile. Good efficiency is achieved by the best possible uniform flow over the cross-section of the catalytic converter unit.

In an advantageous embodiment of the internal combustion engine in accordance with the invention with at least one catalytic converter unit, at least one, preferably all, catalytic converter bodies are especially arranged as an oxidizing converter, preferably as a diesel oxidizing converter.

In a further advantageous embodiment of the internal combustion engine in accordance with the invention, the catalytic converter bodies are arranged in the exhaust gas flow path in a substantially force-free way. Since the catalytic converter bodies are arranged in the catalytic converter unit in a substantially force-free manner, no special demands need to be made on the fixing of the catalytic converter bodies. It is a further advantage of this arrangement that the force-free arrangement does not lead to any thermal induction of tension. Force-free shall be understood in this case as a tension-free installation of the catalytic converter bodies, e.g. by an interlocking connection without welded joints or screwed connections. The catalytic converter bodies can be pushed in a tension-free way into the exhaust gas flow path of example.

In a preferred embodiment of the internal combustion engine, at least one group, preferably all catalytic converter bodies, originates from one plane. The length of the catalytic converter unit is thus reduced. This leads to a lower pressure loss and to a lower influence on the engine output.

The catalytic converter bodies in the catalytic converter unit are arranged in at least one row in a further embodiment of the internal combustion engine. The overall length of the catalytic converter unit is thus reduced. This leads to the advantage that the weight is kept low.

In an especially advantageous embodiment of the invention, the catalytic converter bodies have longitudinal axes, wherein the longitudinal axes of the catalytic converter bodies of a first and every further row form planes with respect to each other which extend substantially in parallel. This leads to a packing of the catalytic converter bodies in the catalytic converter unit which is arranged at maximum density over the cross-section. This arrangement ensures that the pressure loss between the inlet into the catalytic converter and the outlet out of the catalytic converter is lower. This compact configuration of the invention also ensures that the catalytic converter bodies are not destroyed even under very difficult conditions as are provided for example by impacts, especially in operation of the vehicle, or are not impaired with respect to their function.

In a further embodiment of the invention, the cross-section of the catalytic converter unit is provided with the shape of a polygon. Alternatively, the cross-section of the catalytic converter unit can substantially have the shape of a rectangle. It is also possible to arrange the cross-section of the catalytic converter unit substantially in form of a triangle. These arrangements ensure that the areas with active inflow are optimally adjusted to the constructional conditions. A housing for the catalytic converter unit can be avoided in these embodiments, so that the construction can be arranged in a much easier way.

It has proven to be especially advantageous to arrange the cross-section of the catalytic converter unit in a rotationally symmetrical form, especially with a circular cross-sectional form. The cross-section of the catalytic converter body can have the shape of an ellipse, a rectangle or a circular form. The overall space can be better utilized in this way.

In another embodiment of the invention, the catalytic converter bodies in the exhaust gas flow path are arranged in a catalytic converter housing in a substantially force-free way. No major demands are therefore placed on the fixing of the catalytic converter body in the catalytic converter housing. The arrangement of the invention with a catalytic converter housing comes with the advantage that the catalytic converter unit can thus be applied in a simple way like a finished module.

In a further advantageous embodiment of the internal combustion engine in accordance with the invention with at least one catalytic converter unit, the cross-section of the catalytic converter housing has the shape of a polygon. This offers the advantage that a large number of catalytic converter bodies can be arranged in the catalytic converter housing, so that a compact construction is possible. As an alternative to this arrangement, the cross-section of the catalytic converter housing can substantially have the shape of a rectangle or triangle. It is further possible to arrange the cross-section of the catalytic converter housing substantially with a rotationally symmetrical form, especially a circular form, or as an ellipse. The cross-section of the catalytic converter housing is thus adjusted to the constructional conditions.

In accordance with a further embodiment of the internal combustion engine in accordance with the invention with at least one catalytic converter unit, the catalytic converter bodies touch each other in a substantially tangential way. Compactness and better utilization of space are ensured by this arrangement.

In another preferred embodiment of the invention, the plane of the longitudinal axes of the catalytic converter bodies forms an angle with the longitudinal axis of the exhaust gas heat exchanger. This allows a more compact and space-saving construction.

In another preferred embodiment of the invention, the plane of the longitudinal axes of the catalytic converter bodies forms an angle with the longitudinal axis of the exhaust gas recirculation line. The advantage of this configuration is that a compact construction is ensured.

In an especially preferred embodiment of the invention, a first angle between at least one longitudinal axis of the catalytic converter body and the longitudinal axis of the exhaust gas heat exchanger on the one hand and/or a second angle between at least one longitudinal axis of the catalytic converter body and the longitudinal axis of the exhaust gas recirculation line on the other hand are approximately 90°. This embodiment of the invention proves to be especially advantageous because it allows better adaptability.

In a further especially preferred embodiment, the catalytic converter unit is arranged in a deflection area of the exhaust gas flow path, wherein preferably the deflection area is used as 180° deflection. As a result, weight is saved and the overall space is used optimally.

In another especially preferred embodiment of the invention, the catalytic converter unit is partly arranged in the exhaust gas recirculation line and partly in the exhaust gas heat exchanger. An important advantage of this arrangement is that the overall space is utilized very well. The overall space is reduced in size and the construction becomes lighter and more compact. A substantially homogeneous flow profile is provided in this way. Good efficiency of the catalytic converter unit is achieved by the best possible even inflow over the cross-section of the catalytic converter unit. In addition, a lower pressure loss is achieved between the inlet into the catalytic converter unit and the outlet from the catalytic converter unit and there is a lower influence on the engine output.

As an alternative to this embodiment, the catalytic converter unit can be arranged at least predominantly in the exhaust gas recirculation line or arranged at least predominantly in the exhaust gas heat exchanger.

It is understood that the aforementioned features and those to be explained below can be used not only in the respectively indicated combination but also in other combinations or individually without leaving the scope of the present invention.

DRAWINGS

The subject matter in accordance with the invention will be explained below in closer detail by reference to the embodiments and FIGS. 1 to 13 a. The drawings and their description provide further features and advantages of the invention, wherein:

FIG. 1 illustrates a schematic view of an exhaust gas aftertreatment apparatus with a catalytic converter unit arranged in a catalytic converter housing.

FIG. 2 illustrates a schematic view of an exhaust gas aftertreatment apparatus with a catalytic converter unit in which at least three catalytic converter bodies with parallel flow are arranged.

FIG. 2 a illustrates a schematic view of the exhaust gas aftertreatment apparatus in a sectional view along the line IIa-IIa in FIG. 2.

FIG. 3 illustrates a schematic view of a circular cross-sectional shape of the catalytic converter body.

FIG. 4 illustrates a schematic view of a circular cross-sectional shape of the catalytic converter body.

FIG. 5 illustrates a schematic view of an oval cross-sectional shape of the catalytic converter body.

FIG. 6 illustrates a schematic view of a rectangular cross-sectional shape of the catalytic converter body.

FIG. 7 illustrates a schematic view of a cross-section of the catalytic converter unit in form of a polygon.

FIG. 8 illustrates a schematic view of a cross-section of the catalytic converter unit in form of a rectangle.

FIG. 9 illustrates a schematic view of a circular cross-sectional shape of the catalytic converter unit.

FIG. 9 a illustrates a schematic view of a cross-section of the catalytic converter unit in form of a star.

FIG. 10 illustrates a schematic view of an exhaust gas aftertreatment apparatus with a catalytic converter unit arranged in the exhaust gas recirculation line.

FIG. 11 illustrates a schematic view of an exhaust gas aftertreatment apparatus with a catalytic converter unit arranged in the exhaust gas heat exchanger intake port.

FIG. 12 illustrates a schematic view of an exhaust gas aftertreatment apparatus with a catalytic converter unit, wherein the angle between the longitudinal axis of the catalytic converter body and the longitudinal axis of the exhaust gas heat exchanger is 0°.

FIG. 13 illustrates a schematic view of an exhaust gas aftertreatment apparatus with a catalytic converter unit, wherein the angle between the longitudinal axis of the catalytic converter body and the longitudinal axis of the exhaust gas heat exchanger is 90°<α<180°.

FIG. 13 a illustrates a schematic view of an exhaust gas aftertreatment apparatus with a catalytic converter unit, wherein the angle between the longitudinal axis of the catalytic converter body and the longitudinal axis of the exhaust gas heat exchanger is 0°<α<90°.

DESCRIPTION

FIG. 1 schematically illustrates an exemplary embodiment of the exhaust gas aftertreatment apparatus 10 in accordance with the invention of an internal combustion engine which is arranged as a large diesel engine. The exhaust gas aftertreatment apparatus 10 comprises an exhaust gas recirculation line 6 and a catalytic converter unit 1, which is arranged upstream of an exhaust gas heat exchanger 4 with an exhaust gas heat exchanger intake port 3. The direction of flow is indicated by the arrow EGR. In order to reduce hydrocarbons which form an adhesive layer with the exhaust particulates on the cooled inner walls of the exhaust gas heat exchanger 4 that is arranged as an exhaust gas cooler, the catalytic converter unit 1 is appropriately arranged before the exhaust gas heat exchanger 4. The catalytic converter unit 1 is arranged in a catalytic converter housing 5 and comprises three catalytic converter bodies 2 a, 2 b and 2 c which are arranged as diesel oxidizing converters with a respective volume V1, V2, V3, a length L and a cross-sectional area A. The total volume V=V1+V2+V3 of the catalytic converter bodies 2 a, 2 b and 2 c which is required for efficient oxidation is achieved in such a way that the cross-sectional area A is increased, wherein the length L of the three catalytic converter bodies 2 a, 2 b and 2 c with parallel flow are kept as short as possible in respect of their construction in the catalytic converter unit 1. A shorter length of the catalytic converter bodies 2 a, 2 b and 2 c leads to a lower pressure loss in the individual catalytic converter bodies 2 a, 2 b and 2 c.

Elements with equivalent function are provided with the same reference numerals below.

FIG. 2 illustrates an embodiment of the schematically illustrated exhaust gas aftertreatment apparatus 10 in accordance with the invention of an internal combustion engine (not illustrated) which is arranged as a large diesel engine. The internal combustion engine comprises a catalytic converter unit 1 for cleaning the exhaust gases produced during the operation of an internal combustion engine, which catalytic converter unit contains three catalytic converter bodies 2 a, 2 b and 2 c, an exhaust gas recirculation line 6 and an exhaust gas heat exchanger 4, wherein the exhaust gas heat exchanger 4 is arranged as an exhaust gas cooler.

The catalytic converter unit 1 is arranged upstream of the exhaust gas heat exchanger 4 in an exhaust gas flow path, especially an exhaust gas recirculation line 6, wherein the three catalytic converter bodies 2 a, 2 b and 2 c with parallel flow are arranged in a force-free manner packed at maximum density over the cross-section. Force-free shall be understood below as a tension-free installation of the catalytic converter bodies, e.g. by an interlocking connection without a welded joint or screwed connection. The direction of flow of the exhaust gas is indicated by the arrow EGR.

The catalytic converter bodies 2 a, 2 b and 2 c are arranged as diesel oxidizing converters. Their face surfaces 9 are respectively arranged in a common plane 8 according to FIGS. 3 and 4. As is illustrated in FIG. 2 a, the catalytic converter bodies 2 a, 2 b and 2 c touch each other tangentially and are welded into the catalytic converter unit 1 in a gas-tight manner. They have a short length L, which provides a low pressure loss in the individual catalytic converter bodies 2 a, 2 b and 2 c. The catalytic converter unit 1 is welded into a deflection area of the exhaust gas flow path, which is arranged as a 180° deflection. It is partly arranged in the exhaust gas recirculation line 6 and partly in the exhaust gas heat exchanger intake port 3, especially in the catalytic converter receiving section 3 b. The exhaust gas recirculation line 6 and the exhaust gas heat exchanger 4 are appropriately connected to each other via a flange 7 in such a way that the exhaust gas recirculation line 6 is connected to the catalytic converter receiving section 3 b of the exhaust gas heat exchanger intake port 3.

The diffuser section 3 a of the exhaust gas heat exchanger intake port 3 is connected to the exhaust gas heat exchanger 4 by means of a further flange. In accordance with FIG. 2, the angles α and β between at least one longitudinal axis 11 of the catalytic converter bodies 2 a, 2 b and 2 c and the longitudinal axis 12 of the exhaust gas heat exchanger 1 or between at least one longitudinal axis 11 of the catalytic converter bodies 2 a, 2 b and 2 c and the longitudinal axis 13 of the exhaust gas recirculation line 6 are approximately 90°. The catalytic converter bodies 2 a, 2 b and 2 c can have different constructional shapes. In addition to a circular cross-sectional shape as is illustrated in FIG. 3 and FIG. 4, and oval form as illustrated in FIG. 5 or a rectangular form as illustrated in FIG. 6 is possible.

FIGS. 7 to 9 illustrate different possibilities for arrangement of the catalytic converter bodies 2 in the catalytic converter unit 1. The catalytic converter bodies 2 comprise longitudinal axes 11, wherein the longitudinal axes 11 of the catalytic converter bodies 2 of a first and every further row form planes extending in a mutually parallel way. FIG. 7 illustrates the catalytic converter unit 1 with a cross section in form of a polygon. FIG. 8 illustrates a catalytic converter unit 1 with a cross-section in form of a rectangle. FIG. 9 illustrates a catalytic converter unit 1 with a circular cross-section. FIG. 9 a illustrates the catalytic converter unit 1 in form of a star.

FIG. 10 illustrates a further embodiment of a schematically illustrated exhaust gas aftertreatment apparatus 10 in accordance with the invention of an internal combustion engine (not illustrated) which is arranged as a large diesel engine. A catalytic converter unit 1 which contains three catalytic converter bodies 2 a, 2 b and 2 c, an exhaust gas recirculation line 6 and an exhaust gas heat exchanger 4 (not illustrated) are arranged in the exhaust gas flow path, wherein the exhaust gas heat exchanger 4 is arranged as an exhaust gas cooler. The catalytic converter unit 1 is arranged entirely in an exhaust gas recirculation line 6 upstream in the exhaust gas flow path, wherein the three catalytic converter bodies 2 a, 2 b, 2 c with parallel flow are arranged in a force-free manner packed at maximum density over the cross-section. The catalytic converter bodies 2 a, 2 b, 2 c are arranged as diesel oxidizing converters. As is illustrated in FIGS. 3 and 4, the face surfaces 9 of the catalytic converter bodies 2 a, 2 b, 2 c are respectively arranged in a common plane 8. The catalytic converter bodies 2 a, 2 b, 2 c touch each other tangentially and are welded in a gas-tight manner into the catalytic converter unit 1. In order to ensure a low pressure loss in the individual catalytic converter bodies 2 a, 2 b and 2 c, the catalytic converter bodies 2 a, 2 b, 2 c are provided with a short length L.

FIG. 11 illustrates a further embodiment of a schematically illustrated exhaust gas aftertreatment apparatus 10 in accordance with the invention of an internal combustion engine (not illustrated) which is arranged as a large diesel engine. The internal combustion engine comprises a catalytic converter unit 1 which contains three catalytic converter bodies 2 a, 2 b and 2 c, and an exhaust gas recirculation line 6 and an exhaust gas heat exchanger 4 (not illustrated), wherein the exhaust gas heat exchanger 4 is arranged as an exhaust gas cooler. The catalytic converter unit 1 is arranged upstream of the exhaust gas recirculation line 6 in an exhaust gas flow path, especially in the exhaust gas heat exchanger intake port 3 in the catalytic converter receiving section 3 b. The three catalytic converter bodies 2 a, 2 b, 2 c with parallel flow are arranged as diesel oxidizing converters and are arranged in a force-free manner packed at maximum density over the cross-section. Their face surfaces 9 are respectively arranged in a common plane 8, as illustrated in FIGS. 3 and 4. The catalytic converter bodies 2 a, 2 b, 2 c touch each other tangentially and are welded in a gas-tight manner into the catalytic converter unit 1. They have a short length L. This leads to a low pressure loss in the individual catalytic converter bodies 2 a, 2 b and 2 c.

In accordance with a further embodiment which is illustrated in FIG. 12, a schematically illustrated exhaust gas aftertreatment apparatus 10 in accordance with the invention of an internal combustion engine (not illustrated) is illustrated which is arranged as a large diesel engine. The internal combustion engine comprises a catalytic converter unit 1 which contains three catalytic converter bodies 2 a, 2 b, 2 c, and an exhaust gas recirculation line 6 and an exhaust gas heat exchanger 4, wherein the exhaust gas heat exchanger 4 is arranged as an exhaust gas cooler. The catalytic converter unit 1 is arranged upstream of the exhaust gas recirculation line 6 in an exhaust gas flow path, especially in the exhaust gas heat exchanger intake port 3 in its catalytic converter receiving section 3 b. The exhaust gas recirculation line 6 and the exhaust gas heat exchanger intake port 3 are appropriately connected to each other via a flange 7 in such a way that the exhaust gas recirculation line 6 is connected to the catalytic converter receiving section 3 b of the exhaust gas heat exchanger intake port 3. The diffuser section 3 a of the exhaust gas heat exchanger intake port 3 is connected to the exhaust gas heat exchanger 4. The angle α between at least one longitudinal axis 11 of the converter bodies 2 a, 2 b and 2 c and the longitudinal axis 12 of the exhaust gas heat exchanger 1 is approximately 0°. The direction of flow is indicated by the arrow EGR. The catalytic converter bodies 2 a, 2 b, 2 c are arranged as diesel oxidizing converters and are arranged in a force-free manner packed at maximum density over the cross-section. Their face surfaces 9 are respectively arranged in a common plane 8, as illustrated in FIGS. 3 and 4. The converter bodies 2 a, 2 b, 2 c touch each other tangentially and are welded in a gas-tight manner into the catalytic converter unit 1.

In the embodiment according to FIG. 13 a, an exhaust gas aftertreatment apparatus 10 of an internal combustion engine (not illustrated) arranged as a large diesel engine is schematically illustrated. The internal combustion engine comprises a catalytic converter unit 1 for cleaning the exhaust gases produced during the operation of an internal combustion engine, which catalytic converter unit contains three catalytic converter bodies 2 a, 2 b, 2 c, and an exhaust gas recirculation line 6 and an exhaust gas heat exchanger 4. The catalytic converter unit 1 is arranged upstream of the exhaust gas heat exchanger 4, which is arranged as an exhaust gas cooler, in an exhaust gas flow path, especially an exhaust gas recirculation line 6, wherein the three catalytic converter bodies 2 a, 2 b, 2 c with parallel flow are arranged in a force-free manner packed at maximum density over the cross-section. The catalytic converter unit 1 is partly arranged in the exhaust gas recirculation line 6 and partly in the exhaust gas heat exchanger intake port 3 in its catalytic converter receiving section 3 b. The direction of flow is indicated by the arrow EGR. The catalytic converter unit 1 is welded into a deflection region of the exhaust gas flow path. The exhaust gas recirculation line 6 and the exhaust gas heat exchanger 4 are appropriately connected to each other via a flange 7 in such a way that the exhaust gas recirculation line 6 is connected to the catalytic converter receiving section 3 b of the exhaust gas heat exchanger intake port 3. The angle a between at least one longitudinal axis 11 of the catalytic converter bodies 2 a, 2 b, 2 c which are arranged as diesel oxidizing converters and the longitudinal axis 12 of the exhaust gas heat exchanger 4 is less than approximately 90°, especially less than approximately 60°. The size of the angle α is chosen depending on the installation conditions.

In another embodiment of the schematically illustrated exhaust gas aftertreatment apparatus 10 in accordance with the invention of an internal combustion engine (not illustrated) which is arranged as a large diesel engine as illustrated in FIG. 13, the angle a between at least one longitudinal axis 11 of the catalytic converter bodies 2 a, 2 b and 2 c which are arranged as diesel oxidizing converters and the longitudinal axis 12 of the exhaust gas heat exchanger 4 is larger than approximately 90°, preferably 90°<α<180°, and especially larger than approximately 120°.

The invention is not limited to the embodiments as described above, but can rather be applied to further internal combustion engines. It is also possible to combine respective measures of the various embodiments with each other. The invention can be applied generally to internal combustion engines.

LIST OF REFERENCE NUMERALS

1 Catalytic converter unit

2, 2 a, 2 b, 2 c Catalytic converter body

3 Exhaust gas heat exchanger intake port

3 a Diffuser section

3 b Catalytic converter receiving section

4 Exhaust gas heat exchanger (for exhaust gas recirculation)

5 Catalytic converter housing

6 Exhaust gas recirculation line

7 Flange

8 Plane

9 Face surface

10 Exhaust gas aftertreatment apparatus

11 Longitudinal axis of the catalytic converter body

12 Longitudinal axis of the exhaust gas heat exchanger

13 Longitudinal axis of the exhaust gas recirculation line

α, β Angle

V, V1, V2, V3 Volume

L Length of the catalytic converter body

EGR Arrow 

1-21. (canceled)
 22. An internal combustion engine, comprising: an exhaust gas recirculation line; an exhaust gas heat exchanger; a catalytic converter unit configured to clean exhaust gases produced during operation of the internal combustion engine, the catalytic converter unit having a plurality of catalytic converter bodies arranged upstream of the exhaust gas heat exchanger in the an exhaust gas recirculation line and through which the exhaust gas flows, wherein the plurality of catalytic converter bodies are arranged in parallel.
 23. The internal combustion engine of claim 22, wherein each one of the catalytic converter bodies comprises a catalytic converter carrier with catalytic converter material arranged within a catalytic converter cover.
 24. The internal combustion engine of claim 22, wherein the catalytic converter bodies are arranged in a substantially force-free manner in the exhaust gas flow path.
 25. The internal combustion engine of claim 22, wherein the catalytic converter bodies each comprise face areas which are respectively arranged in a common plane.
 26. The internal combustion engine of claim 22, wherein the catalytic converter bodies are arranged in the catalytic converter unit in at least one row.
 27. The internal combustion engine of claim 26, wherein: the catalytic converter bodies comprise longitudinal axes; and the longitudinal axes of a first and every further at least one row form substantially parallel extending planes with respect to each other.
 28. The internal combustion engine of claim 22, wherein the cross-section of the catalytic converter unit is polygonal.
 29. The internal combustion engine of claim 22, wherein the cross-section of the catalytic converter unit is rectangular.
 30. The internal combustion engine of claim 22, wherein the cross-section of the catalytic converter unit is triangular.
 31. The internal combustion engine of claim 22, wherein the cross-section of the catalytic converter unit is rotationally symmetrical.
 32. The internal combustion engine of claim 22, wherein the catalytic converter bodies are arranged in a catalytic converter housing.
 33. The internal combustion engine of claim 22, wherein the catalytic converter bodies abut each other substantially tangentially.
 34. The internal combustion engine of claim 22, wherein a plane of the longitudinal axes of the catalytic converter bodies forms a predetermined angle with the longitudinal axis of the exhaust gas heat exchanger.
 35. The internal combustion engine of claim 34, wherein the predetermined angle is approximately 90°.
 36. The internal combustion engine of claim 22, wherein a plane of the longitudinal axes of the catalytic converter bodies forms a predetermined angle with the longitudinal axis of the exhaust gas recirculation line.
 37. The internal combustion engine of claim 36, wherein the predetermined angle is approximately 90°.
 38. The internal combustion engine of claim 22, wherein: the catalytic converter unit is arranged in a deflection region of the exhaust gas flow path; and the deflection region is arranged as a 180° deflection.
 39. The internal combustion engine of claim 22, wherein: the catalytic converter unit is partially arranged in the exhaust gas recirculation line and partially arranged in an intake port of the exhaust gas heat exchanger; and the intake port comprises a diffuser section (and a catalytic converter receiving section.
 40. The internal combustion engine of claim 39, wherein the catalytic converter unit is arranged at least predominantly in the exhaust gas recirculation line.
 41. The internal combustion engine of claim 39, wherein the catalytic converter unit is arranged at least predominantly in the exhaust gas heat exchanger. 